Apple is going to be holding an event for the press on March 17th and will be previewing iPhone OS 3.0 and the new iPhone SDK. Apple is calling this an “advance preview of what we’re building” so do not expect anything to go live on the 17th, but you will be able to get a sneak peek. The event starts at 10am PST or 1pm EST. The guys over at the Boy Genius Report are saying that you can expect MMS and tethering via bluetooth and USB.